Preparation and assessment of antimicrobial properties of bimetallic materials based on NaY zeolite

The antimicrobial behavior of different pairs of bimetallic materials based on NaY zeolite was assessed in order to optimize the best metal pair composition. The materials were prepared by an ion-exchange method using zeolite Y in sodium form (NaY, 700 nm) with different metals (copper, zinc and silver). The resulting materials were characterized by Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), cyclic voltammetry and chemical analysis, which indicated that the bimetallic metal species were effectively ion exchanged in NaY, with no modification of the zeolite structure. The antimicrobial potential of the materials was evaluated in vitro using the bacteria Escherichia coli and the yeast Saccharomyces cerevisiae as indicator strains. All materials showed good antimicrobial properties with the pair Zn/Ag being the most active among the bimetallic materials tested. The sequence of antimicrobial activities was as follows: Zn0.05Ag-Y > AgZn0.05-Y > AgCu-Y = CuAg-Y > Zn0.05Cu-Y = CuZn0.05-Y = NaY.